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H, S. GRACE.

HAND PIECE PoR DENTAL ENGINES.

Patented Apr..

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Unirse STATES PATENT Carica..

HENRY S. GRACE, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE-HALF TO CHARLES W. DECKER, OF SAME PLACE.

HANDnPIECE FOR DENTAL ENGiNES.

SPECIFICATION forming pari: ci' Letters Patent No. 380,433, dated April 3, 1888.

Application filed May 28, 1887.

To aZZ whom it may concern:

Be it known that I, HENRY S. GRACE, of the city and county of San Francisco, State of California, have invented au Improvement in Hand-Pieces forDent-al-Fngines; and I hereby declare the following to be a full, clear, and exact description of the saine.

My invention relates to a dental implement; and it consists iu the constructions and combinations of devices, which I shall hereinafter fully describe and claim.

Figure l is a longitudinal section of the apparatus. Fig. 2 is an out-side View of the sanne. Fig. 3 shows the point directly connected with the flexible driving-cable so that it may be used as a drill or barring-tool. Fig. 4 shows the point adapted to be used as a plug ger. Fig. 5 shows a mechanism for reversing the direction of the plugging movement and changing its angle. Fig. is an enlarged view of the interior shell and the connecting device intermediate between the parts.

A is the outer cylindrical shell of the handpiece, having the top B at the upper end through which the cable or ilexible drivingshaft C enters to actuate the internal mechanism.

F is the spindle, into the point of which is inserted a split shank or socket which forms a chuck into which the ends of any and all tools which are to be used with the apparatus may be inserted. This chuck may be interchangeable. 'Ihe inner end of this chuck screws into an interior shank, F, and this latter is operated by a milled head, G, at its upper end, by turning which it is drawn up and with it the chuck or socket E, so that as it is drawn into the conical point of the spindle F it is compressed upon the tool so as to hold it firmly, whatever may be its shape or size. This makes it possible to use a great many kinds of tools in a single hand-piece without having the ends especially iitted to any particular holding device.

His a slide which fits outside the cylindrical body A, and moves up or down, so as to eX- pose or cover openings in the side of the body which are just opposite the milled head G, thus allowing the operator easy access to the Serial No. 239,7l2. (Model.)

milled head when it is desired to turn it. In 5o order to connect this lower tool-holding portion of the device with the upper and actuating portion, I employ an intermediate piece,

I, which is formed, as shown in Fig. 6, with the longitudinal projecting bars all around it, 5 5 and the ends of these bars fit into corresponding depressions or sockets on the parts .I and U, as plainly shown in Fig. 6.

The piece I has one end, L, made to act as a hammer when the tool is to be used as a 6o plugger, in which case it is reversed so that the end L is toward the point where the tool is secured, and it then rests upon the end of that portion carrying the tool itself, as is more fully shown in Fig. a.

In order to soften the blow which is given by the plugger, I have introduced between the tool and the mallet or hammer portion leather, wood, or similar substance, as shown at M, which serves as a sort of cushion to re- 7o lieve the disagreeable effects of a blow, making it much pleasanter than when metal strikes against metal. The buder may be upon one or both the meeting ends, or simply placed between them. 7 5

The part .I (shown in Fig. 6, and also in Figs. l and 3,) is in the forni of ayolre having in the head at the lower end of the yoke a square hole at N, which iits over the square shank on the spindle F, so that when the 8o flexible driving cable is connected directly with this portion, as shown in Fig. 3, it will cause the toolto-rotate when it is used as a drill.

All that upper portion or middle body of S5 the hand-piece between the cap B and the toolholding portion and cone D may be omitted and the cable connected directly with this lower portion, the device then being used simply as a drill alone. In Fig. 4 I have shown 9o a similar construction in which the cable is connected with that portion serving as a plugger or mallet, the body or intermediate portion being omitted in this case as well.

In Fig. l the cable or flexible drivin g-shaft C 95 passes in through the head and connects with a shaft carrying aportion O of the clutcli,which slides upon a feather, so that it may be raised o'r depressed by means of a pin which enters a groove in the clutch-ring, and this pin is con-` nected with a sleeve, P, sliding in an angular or Z-shaped slot upon the outside of the exterior case, and passes through the cap B, so

that by raising the sleeve up the clutch is' thrown out of engagement with the part Q, and by moving it down it is thrown into eugagement, so as to drive this part.

R is the cam by which the hammer or mallet is raised as the shaft rotates, and S is the spring by which it is forced down to give the blow when the pin passes over the highest point of the cam.

The part K, referred to and shown in Fig. 6, forms an interior sleeve within the outer casing, within which the spring S and the shaft carrying the operating cani are connected, as shownin Fig. 1. A pin, T, passes through the side of this interior cylindrical sleeve and extends inwardly above the inclines of the cam, so that as the camshaft rotates these inclines will successively. raise the pin, carrying with it the sleeve K and the parts below which are connected therewith.

In order to connect the intermediate sleeve with the part K, I have formed a groove or channel, II, around the lower end of the extension-piece U', which rotates in this partK, as is more plainly shown in Fig. l, and there are corresponding grooves or channels inside the longitudinal bars I, so that a ring lyingin these channels will unite them like a key and hold the parts together. The part U is driven by the lower end of the cam-shaft, which is made square and ts into a corresponding socket in U.

When the device is to be used as a drill or burring-instrunient, the part I is reversed, the hammer portion L then extending toward and into the lower end ofthe part K of the extension thereon, and the opposite end simply engages with the projections and sockets of the part J, thus making the device easily interchangeable.

In order to allow the interior cylindrical sleeve K, which actuates the mallet, to move up and `down within the outer casing when acted upon by the cams R, and at the same time prevent its being turned around within the outer case, I have formed it with a channel or depression at one side, as shown at V, Fig. 6, and into this depression a screw or pin, NV, (shown at Fig. 1,) enters and acts as a guide, thus allowing the sleeve K to move up and down without turning.

The movement of the chuck and the sweep of the blow are regulated by means of the screw d and alock-nut for holding it in place. The yoke J is held on the square shoulder of the spindle F by a nut, e, and lost motion in the spindle is taken up by a nut, f, being screwed down upon the shoulder of the spindle, said nut having threads engaging the inner surface of the cone D, as shown in Fig. l. 4

In some cases it is desirable to use the mallet or plugger in positions where it cannot be operated to advantage in a direct line, and this is effected by means of an extension at right angles with the point D, as shown .in Fig.' 5, with a lever, a, fulcrumed within it, having one end connected with the reciprocating piece, which -is held by the chuck or to'olholder, and the other end is connected with the pluggingtool b, which extends upward or returns parallel with the shank of the `implement, so that through the lever a the blow is given in an opposite direction to the impulse of the mallet.

In order to enable me to change the angle of this tool and use it in different directions, I have hinged the outer portion, X', of the an-` gular extension from the point and fitted it to the part X, so that it may turn about this part and about the pivot of the lever and tool, so that the tool itself, standing between guides upon the hinged portion X, will partakeotV the `motion of this portion and will be caused to point at an angle having any desired degree Y of inclination with the actuating-lever a.

Having thus described my invention, `what I claim as new, and desire to secure by Letters Patent, is-

1. In a dental hand-piece,'the exterior casing, the interior cylinder, within which are fitted the rotary cam shaft and the spiral spring which actuates the mallet, in combination with the spindle having the tool-holder and adjusting mechanism, and the intermediate reversible connecting-piece I, by which the two are united, substantially as described.

2. In a dental hand-piece, the exterior case,

the interior cylinder having the slot and guidingpin upon one side and the cam-shaft and spring fitted to its interior, in combination with the clutch, one portion of which is secured to the end of the cani-shaft,'and the other slides upon a'feather in the drivingshaft, which enters the upper end of the hand` piece, together with the sliding ring and pin; whereby the clutch may be made to engage or disengage with the camshaft, substantially as herein described.

3. In combination with the spindle, the tool-holder, and the connecting devices, as shown, the yoke J, within which the milled head of the chuckoperating screw is fitted to turn, said device having a square opening 4in.

the lower end or cross-bar, whereby it is connected with the spindle, so as to rotate the same by the action of the flexible drivingshaft which connects with this device, sub-` IIO 5. The rotary spindle, tool-holding chuck, In witness whereof I have hereunto set my and the driving mechanism of a dental plughand. ger, in combination with the adjusting nut or T sleevef, engaging a shoulder on said spindle, HEB RY GRACE' 5 and externally threaded, whereby the spindle Witnesses:

may be made to run light and 10st motion be S. H. NOURSE, taken up, substantially as herein described. H. C. LEE. 

